Results of studies carried out in humans' have shown that the ability of plaque to lower the pH of sugar solutions can be affected by the ingestion of cheese or peanuts immediately after sucrose ingestion. The purpose of this study was to determine whether the cariogenicity of diet 2000 could be affected by offering rats snacks of cheese or peanuts between meals of their cariogenic diet. Cheese reduced the incidence of dental caries and the numbers of Step. mutans; peanuts were without effect. Extra snacks of the cariogenic diet enhanced caries.